<!DOCTYPE html>
<!-- 设置了根元素的字体大小为75px -->
<html lang="en" style="font-size: 75px;">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>双栏布局</title>

  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
   .container {
      display: flex;
      justify-content: space-between;
    }
   .column {
      width: 5rem; /* 根据前面设置的根字体大小，这里的5rem相当于375px */
      height: 2rem;
      background-color: green;
      font-size: 20px;
      color: white;
      text-align: center;
      line-height: 2rem;
    }
   .column +.column {
      background-color: pink;
    }
  </style>

</head>

<body>
  <div class="container">
    <div class="column">左侧栏</div>

    <div class="column">右侧栏</div>

  </div>

</body>

</html>
